Cryoadhesive device for left atrial appendage occlusion

ABSTRACT

An epicardial device, system, and method for stabilizing the left atrial appendage during a left atrial appendage ligation/occlusion procedure. A cryoadhesion device including a stabilization element is positioned within the pericardial space proximate the left atrial appendage through subxiphoid access. Once the stabilization element is in contact with the left atrial appendage, the stabilization element is cooled to a temperature that is sufficient to cryoadhere the stabilization element to the left atrial appendage. In this way, the cryoadhesion device stabilizes the left atrial appendage in order to perform left atrial appendage ligation/occlusion with a secondary medical device.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of patent application Ser. No.14/477,071, filed Sep. 4, 2014, and entitled CRYOADHESIVE DEVICE FORLEFT ATRIAL APPENDAGE OCCLUSION, the entirety of which is incorporatedherein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

FIELD OF THE INVENTION

The present invention relates to an epicardial method, system, anddevice for stabilizing the left atrial appendage during a left atrialappendage ligation/occlusion procedure.

BACKGROUND OF THE INVENTION

Patients with atrial fibrillation, particularly patients withnon-valvular atrial fibrillation, are five times more likely of having astroke than patients without atrial fibrillation. This increased risk isbelieved to original from the left atrial appendage (LAA), a muscularpouch within the pericardium and connected to the left atrium of theheart. Blood may pool within the LAA, and this pooled blood may have atendency to form clots, which can dislodge from the LAA and form emboli.In fact, it is believed that over 90% of clots form in the LAA.

Consequently, removing or excluding (occluding) the LAA is believed toreduce the risk of stroke, especially in patients with atrialfibrillation. LAA occlusion (which may also be referred to herein asexclusion or ligation) may be accomplished by using an endocardiallyplaced occlusion device, for example, a Transcatheter Patch (CustomMedical devices, Athens, Greece), the PLAATO™ device (ev3, Sunnyvale,Calif.), or WATCHMAN® device (Boston Scientific, Marlborough, Mass.).Alternatively, LAA occlusion may at least partially involve anepicardially placed occlusion device. There are two commonly usedmethods of performing LAA occlusion: one method uses endocardial andepicardial magnetized guides that stabilize the LAA by the magneticforce between the two guides through the LAA tissue. Once the LAA isstabilized, a snare is passed over the LAA and used to ligate or suturethe LAA (for example, the LARIAT™ (SentreHeart, Inc. Redwood City,Calif.)). The other method involves a purely epicardial approach inwhich, via subxiphoid access, the LAA is identified and inserted into aclamp device (for example, the ATRICLIP® (AtriCure, Inc. West Chester,Ohio)). The clamp then remains implanted within the patient. All ofthese methods are meant to isolate the LAA and prevent blood clots fromexiting the LAA and traveling as emboli through the bloodstream.

Of course, each of these methods has its drawbacks. For example, themagnetized guide technique may accommodate a variety of anatomies, butit requires endocardial access. The clamp technique, on the other hand,may be less versatile, but does not require the more invasiveendocardial access.

It is therefore desirable to provide a method, system, and device forperforming LAA occlusion that involves a purely epicardial approach andis adaptable to a variety of anatomies.

SUMMARY OF THE INVENTION

The present invention advantageously provides an epicardial device,system, and method for stabilizing the left atrial appendage (LAA)during a LAA ligation/occlusion procedure. A device for stabilizing theLAA may include a distal portion configured to be positioned within apericardial space proximate the left atrial appendage, the distalportion including a stabilization element, the stabilization elementbeing configured to cryoadhere to left atrial appendage tissue. Thedevice may further comprise a proximal portion configured to be in fluidcommunication with a source of cryogenic fluid. Further, thestabilization element may include an expandable element, such as aballoon. The stabilization element may further include a fluid deliveryelement within the expandable element, and the fluid delivery elementmay be transitionable between a first delivery configuration and asecond expanded configuration. The expandable element may define a firstface and a second face when the fluid delivery element is in the secondexpanded configuration. The fluid delivery element may define aplurality of apertures, and all of the plurality of apertures may bedirected toward one of the first face and the second face.Alternatively, the stabilization element may include a non-expandablethermally transmissive region, and the stabilization element may includea thermoelectric cooling element in thermal communication with thethermally transmissive region. The stabilization element may define aninterior chamber that is in fluid communication with a source ofcryogenic fluid, the thermally transmissive region being configured tobe in thermal communication with the cryogenic fluid. Further, thestabilization element may have a cross-sectional shape that is one ofelliptical, semicircular, or crescent shaped. The thermally transmissiveregion may be located on one side of the stabilization element.

A system for stabilizing a left atrial appendage of a heart may includea cryoadhesion device including a distal portion configured to bepositioned within a pericardial space proximate the left atrialappendage, the distal portion including a stabilization element, and asource of cryogenic fluid in communication with the stabilizationelement. The distal portion may be configured to be positioned withinthe pericardial space through subxiphoid access. Circulation of fluidwithin the stabilization element may lower the temperature of thestabilization element to a temperature that is sufficient to causecryoadhesion between the stabilization element and the left atrialappendage. The stabilization element may include a balloon defining aninterior chamber and a fluid delivery element located within the ballooninterior chamber and being in fluid communication with the source ofcryogenic fluid, the fluid delivery element defining a plurality ofapertures for the delivery of cryogenic fluid into the balloon interiorchamber. The fluid delivery element may be transitionable between afirst delivery configuration and a second expanded configuration, andthe balloon may define a first face and a second face when the fluiddelivery element is in the second expanded configuration.

An epicardial method of stabilizing a left atrial appendage of a heartmay include positioning a stabilization element of a cryoadhesion devicewithin a pericardial space proximate the left atrial appendage andcooling the stabilization element to a temperature that is sufficient tocause cryoadhesion between the stabilization element and the left atrialappendage. For example, the stabilization element may be positionedwithin the pericardial space through subxiphoid access. Cooling thestabilization element may include circulating cryogenic fluid within thestabilization element. The method may further include occluding the leftatrial appendage with a secondary device. The stabilization element mayinclude a balloon defining an interior chamber and a fluid deliveryelement located within the balloon interior chamber and being in fluidcommunication with the cryogenic fluid, the fluid delivery elementdefining a plurality of apertures for the delivery of cryogenic fluidinto the balloon interior chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 shows the heart, including the left atrial appendage (LAA);

FIG. 2 shows an exemplary system that includes a first embodiment of acryoadhesion device;

FIG. 3 shows a cryoadhesion device in an expanded configuration;

FIG. 4 shows a side view of the cryoadhesion device of FIG. 3 ;

FIG. 5 shows the cryoadhesion device of FIG. 3 in a partially retractedconfiguration;

FIG. 6 shows the cryoadhesion device of FIG. 3 in a completely retractedconfiguration;

FIG. 7 shows insertion of a cryoadhesion device via subxiphoid access;

FIG. 8 shows a close-up view of placement of the first embodiment of thecryoadhesion device in contact with the LAA;

FIG. 9 shows a secondary device being positioned for ligation/occlusionof the LAA;

FIG. 10 shows ligation/occlusion of the LAA using the secondary devicewith the first embodiment of the cryoadhesion device in contact with theLAA;

FIG. 11 shows an exemplary system that includes a second embodiment of acryoadhesion device;

FIG. 12 shows a stylized cross-sectional view of a first configurationof the second embodiment of a cryoadhesion device and a secondary devicewithin a guide sheath;

FIG. 13 shows a stylized cross-sectional view of a second configurationof the second embodiment of a cryoadhesion device and a secondary devicewithin a guide sheath;

FIG. 14 shows a stylized cross-sectional view of a third configurationof the second embodiment of a cryoadhesion device and a secondary devicewithin a guide sheath;

FIG. 15 shows a stylized cross-sectional view of a fourth configurationof the second embodiment of a cryoadhesion device and a secondary devicewithin a guide sheath;

FIG. 16 shows a stylized cross-sectional view of the first, second,third, and fourth configurations of the second embodiment of acryoadhesion device located between the LAA tissue and the pericardium;

FIG. 17 shows a close-up view of placement of the second embodiment ofthe cryoadhesion device in contact with the LAA; and

FIG. 18 shows ligation/occlusion of the LAA with a secondary device withthe second embodiment of the cryoadhesion device in contact with theLAA.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1 , a human heart is shown. The heart includes aleft atrial appendage (LAA) (also sometimes referred to as the leftauricular appendix, auricular, or left auricle). The LAA is a small,muscular pouch within the pericardium that opens into the left atrium.As previously discussed, most emboli are believed to originate from theLAA, and those with atrial fibrillation are at the most risk of having astroke. Therefore, it may be desirable to exclude, or isolate, the LAAfrom the patient's bloodstream to reduce the risk of emboli escapingfrom the LAA.

Referring now to FIG. 2 , an exemplary system that includes a firstembodiment of a cryoadhesion device is shown. The system 10 maygenerally include a cryoadhesion device 12 in fluid communication with aconsole 14. The device 12 may include an elongate body 16 having aproximal portion 18 and a distal portion 20, a flexible and resilientfluid delivery element 22, and an expandable element 24. The expandableelement 24, for example, a cryoballoon, may be coupled to the distalportion 20 of the elongate body 16. The fluid delivery element 22 may bein fluid communication with a fluid delivery conduit 26 and may beslidably disposable or disposed within the elongate body 16, such thatadvancement of the fluid delivery element 22 and fluid delivery conduit26 within the elongate body 16 may extend the fluid delivery element 22out the distal opening 30 of the elongate body 16. Additionally oralternatively, the cryoadhesion device 12 may be passed through a guidesheath, such that advancement of the elongate body 16 of thecryoadhesion device 12 within the guide sheath may likewise advance thefluid delivery element 22 out the distal end of the guide sheath toexpand the fluid delivery element 22 and retraction of the elongate body16 of the cryoadhesion device 12 within the guide sheath may likewiseretract the fluid delivery element 22 back into the guide sheath toretract the fluid delivery element 22 (as shown and described in greaterdetail in FIGS. 3-6). The expandable element 24 may also be in fluidcommunication with a fluid recovery conduit 32.

The device 12 may also include one or more electrodes 34 for monitoringan electrical signal from the LAA to obtain information such asconfirmation of proper placement of the device onto LAA tissue, and forvisualization with a navigation system, such as NAVX™ (St. Jude Medical,Inc., St. Paul, Minn.). The one or more electrodes may also be used todetermine whether occlusion of the LAA has occurred. For example, theLAA may be stabilized or secured by the cryoadhesive device, and then aclamp or clip may be used to occlude the LAA. When the LAA is occluded,the one or more electrodes 34 may detect very few or no electricalsignals from the LAA tissue. Conversely, if the one or more electrodes34 detect a normal amount of electrical signals, the system 10 may alertthe operator that the LAA is not occluded.

The device 12 may further include a handle 36 coupled to the proximalportion 18 of the elongate body 16. The handle 36 may include one ormore knobs, wheels, buttons, or other actuators 38 for navigation andmanipulation of the device 12. For example, the one or more actuatorsmay be in mechanical communication with one or more steering elements,such as one or more pull wires 40, rods, or the like.

The console 14 may include a cryogenic fluid source 46 in fluidcommunication with the fluid delivery conduit 26, a fluid recoveryreservoir 48 in fluid communication with the fluid recovery conduit 32.It will be understood that the fluid recovery reservoir 48 may belocated external to the console 14; however, for simplicity, any elementthat is not included in the cryoadhesion device may be referred to asbeing a part of the console 14. The cryogenic fluid source 46 may be,for example, a nitrous oxide (N₂O) or carbon dioxide (CO₂) cartridge,and the cryogenic fluid source 46 may be located within the console 14,external to the console 14, or within the cryoadhesion device handle 36.The cryogenic fluid source 46 may be lower-volume cartridge, becausecryoadhesion without ablation may be achieved with a low cryogenic fluidflow. For example, cryoadhesion may start to occur at approximately 0°C., which is warmer than temperatures required for cryoablation.Alternatively, the device 12 may be used with an existing cryoablationsystem, such as one having larger fluid tanks. Temperatures lower thanapproximately −30° C. may be used, as no detrimental effect ofcryoablation to the LAA is expected before occlusion occurs. Further,the console 14 may include an energy source 50 that is in electricalcommunication with the one or more electrodes 34 and a vacuum source 52that is in fluid communication with the expandable element 24 and thefluid recovery conduit 32.

The console 14 may also include one or more computers 54 having one ormore processors 56 that receive data from the one or more electrodes 34and/or one or other sensors throughout the system (for example,temperature or pressure sensors). The one or more processors 56 may alsoprocess received data using one or more algorithms to, for example,determine the temperature of the expandable element 24, whether thedevice 12 is cryoadhered to the LAA tissue, if the LAA has beensuccessfully occluded, if there is a leak in the system, and/or othersystem and/or anatomic parameters. The console 14 may also include oneor more displays 58 and user input devices 60, such as buttons, knobs,scroll wheels, keyboards, mice, touchscreens, or the like. The console14 may communicate received and/or processed data to the operator, suchas through a display screen 58 and/or one or more audible or visualalerts.

Referring to FIGS. 3-6 , the first embodiment of the cryoadhesion deviceis shown in more detail. As shown and described in FIG. 2 , the device12 may include an expandable element 24 coupled to the distal portion 20of the elongate body 16 and a flexible and resilient fluid deliveryelement 22. The fluid delivery element 22 may either be that slidablyreceived or receivable within the elongate body 16 or immovably disposedwithin the elongate body 16. In either configuration, the fluid deliveryelement 22 may be in fluid communication with the fluid delivery conduit26. As shown in FIG. 3 , the fluid delivery element 22 may have a loopshape when the fluid delivery conduit 26 is advanced within the elongatebody 16, thereby extending the fluid delivery conduit 22 out of theelongate body distal opening 30. The configuration shown in FIG. 3 maybe referred to as the expanded configuration.

The expandable element 24 may be, for example, a balloon that isdisposed over the fluid delivery element 22, and the fluid deliveryelement 22 and the balloon 24 may collectively be referred to as thestabilization element 64. The stabilization element 64 may have alongitudinal axis that is coaxial with the longitudinal axis of theelongate body 16. That is, the device 12 as whole may have a singlelongitudinal axis 66, as shown in FIG. 3 . When in the expandedconfiguration, the stabilization element 64 may have a flat orpaddle-like shape. For example, the stabilization element 64 may definea flattened or planar first face 70, a flattened or planar second face72, and an edge 74 between the first 70 and second 72 faces. The edge 74may assume the curvature of the fluid delivery element 22, and the widthof the edge 74 may be determined at least in part by the diameter of thefluid delivery element 22 and the thickness of the balloon 24 material.FIG. 4 shows a side view of the stabilization element 64, and it can beseen that the edge 74 may have a width that is smaller than the width ofthe first 70 and second 72 faces of the stabilization element 64.

Although the first 70 and second 72 faces of the stabilization element64 may have the same thickness, in an alternative embodiment, one facemay have a thickness that is greater than the other. For example, theballoon 24 may be manufactured such that the balloon material of thefirst face 70 is thicker than the balloon material of the second face72. During use, the thinner second face 72 may be placed in contact withthe LAA tissue. Conversely, the thicker balloon material of the firstface 70 may have an insulative effect, and this warmer face may beplaced in contact with non-target tissue, such as the pericardium. Thewarmer first face 70 may be less likely to cryoadhere to non-targettissue than the thinner second face 72, which may avoid collateraldamage and patient discomfort.

When the stabilization element 64 is in the expanded configuration,cryogenic fluid may be circulated within the balloon interior chamber76. Although circulating cryogenic fluid within the balloon interiorchamber 76 may be referred to as “inflating” the balloon, it will beunderstood that the cryogenic fluid may be circulated at a flow ratethat does not expand, or only slightly expands, the balloon beyond thewidth W_(FDE) and the diameter D_(FDE) of the fluid delivery element 22.That is, the paddle-like shape of the balloon 24 (having a flattened orplanar first and second faces 70, 72) may be maintained at least in partby the expanded fluid delivery element 22 regardless of whethercryogenic fluid is circulated within the balloon chamber 76. Further,the vacuum source 52 may be activated during the LAA occlusion procedureto ensure that the stabilization element 64 is maintained in thepaddle-like or flattened configuration when cryogenic fluid iscirculated within the balloon chamber 76.

The fluid delivery element 22 may include a plurality of fluid deliveryports or apertures 78 for the delivery of cryogenic fluid from the fluiddelivery element 22 into the balloon chamber 76. For example, the fluiddelivery element 22 may include a wall 80 through which the plurality ofapertures 78 extends. That is, each aperture 78 may extend through thewall 80 from an inner lumen of the fluid delivery element 22. Theplurality of apertures 78 may be directed toward the interior of thechamber 76 and/or an inner surface of the balloon 24. In a non-limitingexample, the plurality of apertures 78 may be directed toward the innersurface of either the first face 70 or the second face 72 of theballoon. As described in more detail below, one of the stabilizationelement faces 70, 72 may be cryoadhered to LAA tissue because the faces70, 72 offer the most surface area for binding the balloon 24 andtissue. Therefore, the plurality of apertures 78 may direct thecryogenic fluid to the inner surface of one of the faces 70, 72 tomaximize cooling potential of an area of the stabilization element 64that will most efficiently stabilize the LAA. In the non-limitingembodiment shown in FIG. 4 , the plurality of apertures 78 may bedirected toward the inner surface of the first face 70 of the balloon24. However, it will be understood that the plurality of apertures 78may have any suitable configuration, such as alternating (every otheraperture 78 being directed to the same one of the first 70 and second 72faces), helically arranged, directed toward the center of the chamber76, or the like. Each of apertures 78 may have the same or differentdiameters, and may be round, rectangular, slit-like, helically arrangedslits, or any other suitable configuration.

Referring now to FIGS. 5 and 6 , the stabilization element 64 is shownbeing retracted within or extended out of a guide sheath 82. Asdescribed above, the fluid delivery element 22 and the fluid deliveryconduit 26 may be slidably received or receivable within the elongatebody 16, such that advancement or retraction of the fluid deliveryconduit 26 may likewise advance or retract the fluid delivery element22. Additionally or alternatively, the cryoadhesion device 12 may bepassed through a guide sheath 82, such that advancement of the elongatebody 16 of the cryoadhesion device 12 within the guide sheath 82 maylikewise advance the stabilization element 64 out the distal end of theguide sheath 82 to expand the fluid delivery element 22 and retractionof the elongate body 16 of the cryoadhesion device 12 within the guidesheath 82 may likewise retract the stabilization element 64 back intothe guide sheath 82 to retract the fluid delivery element 22. The fluiddelivery element 22 may be composed of a material such as Nitinol orpolyamide tubing that has a first neutral configuration, which may bethe expanded configuration. The inner diameter of the guide sheathD_(IGS) may be less than the diameter D_(FDE) of the fluid deliveryelement 22 when the fluid delivery element 22 is in the expandedconfiguration. As such, when the fluid delivery element 22 is retractedwithin, and therefore constricted by, the guide sheath, the fluiddelivery element 22 may collapse or fold into an at least substantiallylinear second configuration (this retracted configuration is shown inFIG. 6 ).

FIG. 5 shows a configuration in which the stabilization element 64 ispartially retracted within the guide sheath. The flexible nature of thematerial from which the fluid delivery element 22 is composed will allowthe fluid delivery element 22 to fold into a configuration that isnarrow enough to fit within the elongate body 16 (or elongate bodylumen). However, this folding may be facilitated by a pivot or bendjoint 84, which may be located at the distalmost point in the fluiddelivery element 22 (as shown in FIGS. 3, 5, and 6 ). In embodiments inwhich the fluid delivery element 22 includes a bend joint 84, the fluiddelivery element 22 lumen may be bifurcated to include a first lumenportion extending from the fluid delivery conduit 26 to a locationproximate the bend joint 84 on a first side of the fluid deliveryelement 22, and a second lumen portion extending from the fluid deliveryconduit 26 to a location proximate the bend joint 84 on a second side ofthe fluid delivery element 22. When at least substantially the entirefluid delivery element 22 is extended beyond the distal opening 30 ofthe elongate body 16, the resilient nature of the material from whichthe fluid delivery element 22 is composed may cause the fluid deliveryelement 22 to expand back to the first neutral configuration (that is,the expanded configuration). Additionally or alternatively, thedeployment and retraction of the fluid delivery element 22 may beaccomplished using a push/pull wire that is in contact with the bendjoint 84 at a first end and is attached to an activation mechanism inthe handle 36 at a second end.

Referring now to FIGS. 7-10 , insertion and placement of thecryoadhesion device 12 are shown. The device 12 may be positioned in thepericardial space (that is, between the pericardium and the heart)proximate the LAA. For example, the device 12 may be advanced through aguide sheath 82 that is inserted into the patient's body before thecryoadhesion device 12. As shown in FIG. 7 , the device 12 may beinserted, within the guide sheath 82, via subxiphoid access into thepericardial space and positioned at the target treatment site proximateor in contact with the LAA, which is adjacent to the left atrium.Inserting the device into the patient's body via subxiphoid access maybe less invasive and traumatic to the patient than other means ofaccess, such as a thoractomy. Although the device 12 is not specificallyshown within the guide sheath 82 for simplicity, it will be understoodthat the device 12 may remain within the guide sheath 82 until thedevice 12 is extended beyond the guide sheath 82 at the target treatmentsite. During navigation through the patient's body and placement at thetarget treatment site, the stabilization element 64 may be in theretracted configuration. Once at the target treatment site, the fluiddelivery element 22 may be advanced out the elongate body distal opening30, which may transition the stabilization element 64 to the expandedconfiguration.

Then, cryogenic fluid may be circulated within the balloon chamber 76 toreduce the temperature of the stabilization element 64 to a temperaturesufficient to cryoadhere the balloon 24 to the LAA tissue (as shown inFIG. 8 ). Cryoadhesion between the stabilization element 64 and the LAAmay be referred to as stabilization of the LAA, because the cryoadhesionallows the operator to use the device 12 to move and position the LAAfor occlusion, with movement of the device 12 likewise moving the LAA.The elongate body 16 may be composed of one or more materials that givethe elongate body 16 a stiffness or durometer that allows the operatorto press the stabilization element 64 against the LAA tissue without theelongate body 16 collapsing. Further, unlike commonly used prior artmethods, the present method does not use excessive mechanical force orsuction force to stabilize the LAA, thereby reducing the likelihood oftearing or injuring the LAA tissue, which can be very thin and delicate.Further, the larger surface area of the paddle-like stabilizationelement 64 may distribute any applied force to a larger area of LAAtissue, including stronger trabeculated muscle of the LAA. Once the LAAis stabilized, a secondary device 94 may be used to encircle the base ofthe LAA, thereby occluding the LAA. As a non-limiting example, thedistal loop 96 of a snare-type secondary device 94 may be fed over theelongate body 16 of the cryoadhesion device 12 (as shown from the sidein FIG. 9 ), and then the loop 96 may be tightened around the base of,and thereby occlude, the LAA (as shown from the side in FIG. 10 ).Although a snare-type secondary device 94 is shown in FIG. 9 , it willbe understood that a clamp device or other ligation/occlusion devicealternatively may be used. Further, the cryoadhesion device 12 and thesecondary device 94 may be advanced to the target treatment site throughthe same sheath 82.

Referring now to FIGS. 11-18 , a second embodiment of a cryoadhesiondevice is shown. The device second embodiment may be a focal-type device100 with a non-expandable stabilization element 102. However, all otheraspects of the system 10 not discussed herein may be as shown anddescribed in FIG. 2 . The cryoadhesion device 100 shown in FIGS. 11-18may generally include an elongate body 16 that includes a stabilizationelement 102 that includes one or more thermally transmissive regions orelements at the distal portion 20. As a non-limiting example, thestabilization element may be one or more than one discrete electrodes orareas composed of material that are capable of reaching cryoadhesiontemperatures (for example, approximately −30° C.), such as metal. Forexample, the stabilization element 102 may define an interior chamber104 in thermal communication with the one or more thermally transmissiveregions, which may be composed of a metal such as platinum, gold,copper, other such metals and/or alloys thereof, or thin polymers suchas PTFE, nylon, polyurethane, polyamide, polyester, or other suchcompounds that can be shaped into cooling elements. Cryogenic fluid maybe circulated within the interior chamber 104 and may cool thestabilization element 102 to a temperature sufficient to cryoadhere thestabilization element 102 to the LAA tissue, as described above.Additionally or alternatively, the stabilization element 102 may includeone or more thermoelectric cooling elements 106, such as Peltierelements, in thermal communication with the stabilization element 102(as shown in FIG. 11 ). The stabilization element 102 may entirely orpartially encircle the outer circumference of the elongate body. In thenon-limiting example shown in FIG. 11 , the stabilization element 102may include one thermally transmissive region that includes the distaltip of the device 100.

Referring now to FIGS. 12-16 , stylized cross-sectional images ofseveral stabilization element configurations are shown. In addition tothe cryoadhesion device 100, a stylized cross-sectional image of asecondary device 94 is also shown within the sheath. These images arereferred to as being stylized, because they are simplified forillustration and may not show every element of the devices 100, 94.Further, although the secondary device 94 is shown as having a circularcross section in each of FIGS. 12-15 , it will be understood that thesecondary device 94 may have any suitable cross-sectional shape.

As non-limiting examples, the stabilization element 102 of the device100 may have a circular cross section (FIG. 12 ), an elliptical crosssection (FIG. 13 ), a semicircular cross section (FIG. 14 ), or acrescent-shaped cross section (FIG. 15 ). Although the stabilizationelement 102 cross sections are shown, it will be understood that theelongate body of the cryoadhesion device 100 may also have thecross-sectional shapes shown in FIGS. 12-16 . A stabilization element102 having any of these shapes may be created by A device 100 having anelliptical, semicircular, or crescent-shaped cross section may requireless space within the sheath 82; therefore, a sheath 82 used toaccommodate the secondary device 94 and a cryoadhesion device 100 havingan elliptical, semicircular, or crescent-shaped cross section may have asmaller diameter D₂ than a diameter D₁ of a sheath 82 used toaccommodate the secondary device 94 and a cryoadhesion device 100 havinga circular cross section. Further, a sheath 82 used to accommodate thesecondary device 94 and a cryoadhesion device 100 having acrescent-shaped cross section may have a smaller diameter D₃ than asheath 82 used to accommodate the secondary device 94 and a cryoadhesiondevice 100 having an elliptical or semicircular cross section (D₂). As anon-limiting example, D₁ may be 20 French whereas D₂ may be 13-17French. This effect may be important if the patient's anatomy cannotaccept a larger-diameter sheath.

As shown in FIG. 16 , although the semicircular cross-sectional shapemay be more difficult to manufacture than the circular or ellipticalcross-sectional shapes, the semicircular cross-sectional shape may allowfor very good contact with the LAA and less contact with thepericardium. Further, even though the crescent-shaped cross-sectionalshape may be the even more difficult to manufacture than thesemicircular cross-sectional shape, the crescent-shaped cross-sectionalshape may allow for good contact with the LAA and very little contactwith the pericardium. Less contact with the pericardium may be desirablebecause it reduces the risk that the stabilization element 102 maybecome inadvertently adhered to the pericardium. A lack of or minimaladhesion between the stabilization element 102 and the pericardium mayhelp provide full access to the LAA by secondary devices during aligation/occlusion procedure. Further, similar to that discussed aboveregarding the expandable stabilization element 64, one side of thenon-expandable stabilization element 102 may be insulated or may notinclude any thermally transmissive regions to avoid cryoadhesion betweenthe stabilization element 102 and non-target tissue. As a non-limitingexample, the one or more thermally transmissive regions may be locatedaround less than the entire circumference of a stabilization element 102having a circular cross section, or on the convex side of astabilization element 102 having a crescent-shaped cross section.

Referring now to FIGS. 17 and 18 , placement of the cryoadhesion devicein contact with the LAA and LAA ligation/occlusion are shown. Like thefirst embodiment of the cryoadhesion device 12 shown in FIGS. 7-9 , thesecond embodiment of the cryoadhesion device 100 may be positioned inthe pericardial space proximate the LAA. For example, the device 100 maybe advanced through a guide sheath 82 to the target treatment site viasubxiphoid access. The device 100 may be delivered using a guide sheath82 or may be navigated to the target treatment site without a guidesheath 82. Although the device 100 does not include an expandableelement, cryogenic fluid may be circulated within the interior chamber104 to reduce the temperature of the stabilization element 102 to atemperature sufficient to cryoadhere the stabilization element 102 tothe LAA tissue (as shown in FIG. 17 ), thereby stabilizing the LAA. Theelongate body 16 of the device 100 may be composed of one or morematerials that give the elongate body 16 a stiffness or durometer thatallows the operator to press the stabilization element 102 against theLAA tissue without the elongate body 16 collapsing. Once the LAA isstabilized, a secondary device 94 may be used to encircle the base ofthe LAA, thereby occluding the LAA. Although a snare-type secondarydevice 94 is shown in FIG. 18 , it will be understood that a clampdevice or other ligation/occlusion device alternatively may be used.Further, the cryoadhesion device 100 and the secondary device 94 may beadvanced to the target treatment site through the same sheath 82.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. An epicardial method of stabilizing a left atrialappendage of a heart, the method comprising: positioning a stabilizationelement of a cryoadhesion device within a pericardial space proximatethe left atrial appendage, the stabilization element including: anexpandable element, and a fluid delivery element disposed in an interiorchamber of the expandable element, the fluid delivery element having adistal end with a bend joint and a wall defining one or more aperturesconfigured to deliver a fluid in the interior chamber, the bend jointdisposed in the interior chamber of the expandable element when thefluid delivery element is in an expanded configuration, the fluiddelivery element including a bifurcated lumen having a first lumenportion extending from a fluid delivery conduit to a location proximatethe bend joint on a first side of the fluid delivery element and asecond lumen portion extending from the fluid delivery conduit to alocation proximate the bend joint on a second side of the fluid deliveryelement, when the fluid delivery element is in a retractedconfiguration, the first lumen portion and the second lumen portionbending via the bend joint to fold the fluid delivery element, coolingthe stabilization element to a temperature that is sufficient to causecryoadhesion between the stabilization element and the left atrialappendage.
 2. The method of claim 1, wherein cooling the stabilizationelement includes circulating cryogenic fluid within the stabilizationelement.
 3. The method of claim 2, wherein the expandable elementincludes: a balloon defining the interior chamber; and wherein the fluiddelivery element located within the balloon interior chamber is in fluidcommunication with the cryogenic fluid and wherein the plurality ofapertures deliver the cryogenic fluid into the balloon interior chamber.4. The method of claim 1, wherein the fluid delivery element istransitionable between a first delivery configuration and a secondexpanded configuration.
 5. The method of claim 1, wherein thestabilization element is positioned within the pericardial space throughsubxiphoid access.
 6. The method of claim 1, further comprising:occluding the left atrial appendage with a secondary device.
 7. Themethod of claim 1, wherein the expandable element has: a planar firstface with a continuous surface defining a plane; a planar second faceopposite the planar first face and having a continuous surface defininga plane; and an edge between the planar first face and the planar secondface, the planar first face lying in a second plane that is parallel tothe first plane and the planar second face lying in a third plane thatis parallel to each of the first and second planes, the planar firstface, the planar second face, and the edge defining an interior chamber.8. The method of claim 7, further comprising occluding the left atrialappendage with a secondary device, wherein the secondary device includesa distal portion having a width that is greater than a widest portion ofeach of the planar first face and the planar second face such that thecryoadhesion device and stabilization element extend through the distalportion of the secondary device and the distal portion of the secondarydevice encircles and occludes at least a portion of the left atrialappendage when the stabilization element is cryoadhered to the leftatrial appendage.
 9. An epicardial method of stabilizing a left atrialappendage of a heart, the method comprising: positioning a stabilizationelement of a cryoadhesion device within a pericardial space proximatethe left atrial appendage, the stabilization element being configured tocryoadhere to the left atrial appendage, the stabilization elementincluding: an expandable element having: a planar first face with acontinuous surface defining a plane; a planar second face opposite theplanar first face and having a continuous surface defining a plane; andan edge between the planar first face and the planar second face, theplanar first face lying in a second plane that is parallel to the firstplane and the planar second face lying in a third plane that is parallelto each of the first and second planes, the planar first face, theplanar second face, and the edge defining an interior chamber; a fluiddelivery element disposed in the interior chamber, the fluid deliveryelement having a distal end with a bend joint and a wall defining aplurality of apertures configured to deliver a fluid in the interiorchamber and being transitionable between a loop-shaped firstconfiguration and a linear second configuration; and a secondary deviceincluding a distal portion having a width that is greater than a widestportion of each of the planar first face and the planar second face suchthat the cryoadhesion device and stabilization element extend throughthe distal portion of the secondary device and the distal portion of thesecondary device encircles and occludes at least a portion of the leftatrial appendage when the stabilization element is cryoadhered to theleft atrial appendage; and a source of cryogenic fluid in communicationwith the stabilization element cooling the stabilization element to atemperature that is sufficient to cause cryoadhesion between thestabilization element and the left atrial appendage; and occluding theleft atrial appendage with the secondary device.
 10. The method of claim9, wherein circulation of fluid within the stabilization element lowersa temperature of the stabilization element to a temperature that issufficient to cause cryoadhesion between the stabilization element andthe left atrial appendage.
 11. The method of claim 10, wherein the fluiddelivery element is in fluid communication with the source of cryogenicfluid.
 12. The method of claim 10, wherein the stabilization element ispositioned within the pericardial space through subxiphoid access.